Key points are not available for this paper at this time.
Partial 16S ribosomal ribonucleic acid sequences were determined for Campylobacter concisus, Campylobacter fetus subsp. intestinalis, Campylobacter sputorum subsp. bubulus, Wolinella curva, Wolinella recta, Wolinella succinogenes, Bacteroides gracilis, and Bacteroides ureolyticus. These sequences were compared with previously published sequences of Campylobacter laridis, Campylobacter jejuni, Campylobacter coli, Campylobacter pylori, Thiovulum sp., Escherichia coli, and Bacteroides fragilis, and percentages of homology were calculated. With the exception of C. pylori, all of the campylobacters formed a tight phylogenetic cluster. Within this cluster were the following organisms that have been classified as species of Wolinella and Bacteroides: W. curva, W. recta, B. gracilis, and B. ureolyticus. The average level of interspecies homology within this group was 94.4%. W. succinogenes and C. pylori formed a second cluster with a level of interspecies homology of 90.4%. The average level of homology of the W. succinogenes-C. pylori cluster with species of the campylobacter cluster was 85.1%. Thiovulum sp. was only 83% homologous with either of the two clusters. Based upon the sequence data, we suggest that all members of the campylobacter cluster should be placed in the genus Campylobacter. However, formal resolution of the taxonomic status of the campylobacter cluster may require additional information provided by other experimental methods.
Paster et al. (Fri,) studied this question.